Method for preparing functionalized polyorganosiloxane resins by redistribution in the presence of at least one triflic acid derivative

ABSTRACT

The present invention relates to a process for preparing functionalized polyorganosiloxane (POS) resins comprising units M: (R 3 SiO 1/2 ) Q: (SiO 4/2 ) and M′: (Y a R 3−a SiO 1/2 ) and optionally D: (R 2 SiO 2/2 ) and/or D′: (RYSiO 2/2 ) and T: (RSiO 3/2 ) and/or T′: (YSiO 3/2 ), with, in these units: R=C 1 -C 10  alkyl or a C 8 -C 12  aryl and Y a functional group (e.g.: Si—H), 
     by redistribution of POS resins using POSf bearing functional units M′ and/or D′ and/or in the presence of an acid catalyst of the trifluoromethane-sulfonimide (TFSI) type. 
     The present invention also relates to the aforementioned catalyst system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/509,071, filed Jun. 17, 2005, now allowed, which is the U.S. nationalstage of International Application No. PCT/FR03/00889, filed Mar. 20,2003, and claims priority under 35 U.S.C. § 119(a)-(d) of French PatentApplication No. 02/03771, filed Mar. 26, 2002, said applications beingincorporated by reference herein in their entireties and relied upon.

Reference is also made to commonly assigned application Ser. No.10/509,060 (Attorney Docket No. 0070681000014), which is the U.S.national stage of International Appln. No. PCT/FR03/00888, filed Mar.20, 2003 and which was concurrently filed with parent application Ser.No. 10/509,071 on Jun. 17, 2005, as well as its continuation Appln. No.______ (Attorney Docket No. 0070681-000098) concurrently filed herewith.

The field of the invention is that of the production of silicone orpolyorganosiloxane resins, referred to hereinbelow as POS resins. ThePOS resins more especially targeted are those comprising siloxyl unitsM: (R₃SiO_(1/2)) and optionally D: (R₂SiO_(2/2)) and/or T: (RSiO_(3/2)),said resins moreover being functionalized, i.e. they comprise units M′:(Y_(a)R_(3−a)SiO_(1/2)) and optionally D′: (RYSiO_(2/2)) and/or T:(YSiO_(3/2)); Y representing in these formulae a functional group, forexample a hydrogen or a vinyl, R a hydrocarbon-based group and a=1 or 2.

These functional silicone resins MQ may be liquid or solid at roomtemperature. They have been known for a very long time and are currentlyused in many applications, for instance in electrical insulatingvarnishes, heat-resistant coatings, encapsulating materials forsemiconductor components, etc.

The functional MQ POS resins (MM′Q) whose production forms the subjectof the present invention may also comprise siloxyl units D and/or T, oreven functionalized siloxyl units D′ and/or T′.

The main routes of access to functional MQ resins are currentlyprocesses of condensation/-hydrolysis starting with sodium silicate oralkyl silicate (U.S. Pat. No. 2,676,182, U.S. Pat. No. 2,814,601, U.S.Pat. No. 2,857,356, U.S. Pat. No. 4,707,531). These techniques are notwithout drawbacks, especially in terms of ease of use, cost andproduction of ecotoxic and/or hazardous effluents.

However, an alternative, which is attractive in principle, to thesecondensation/hydrolysis techniques exists, namely the redistribution ofPOS oils in a POS resin comprising MQ units.

By way of illustration of this route of functionalization of resins ofMQ type by redistribution, mention may be made of U.S. Pat. No.4,774,310, U.S. Pat. No. 5,494,979 (≈EP-A-0 617 094) and U.S. Pat. No.5,510,430.

U.S. Pat. No. 4,774,310 describes the preparation of Si—H functionalizedresins by redistribution of tetramethyldisiloxane (M′₂) in an MQ resindissolved in an organic solvent, in the presence of triflic acid orperfluoroalkanesulfonic acid (TFOH). The reaction medium is heated to atemperature of between 50 and 100° C. and the triflic acid catalyst isthen neutralized with NaHCO₃. The MM′Q resins thus obtained may reactwith organic or organosiloxane substances bearing olefin unsaturation(column 2, line 66 to column 3, line 3). Said patent also makes a vagueand general allusion to supported acid catalysts (column 2, line 18).

U.S. Pat. No. 5,494,979 (≈EP-A-0 617 094) discloses the preparation ofMQ resins functionalized with acrylate radicals, by redistribution ofpolydiorganosiloxane oils bearing units D and units D^(acrylate): MD_(x)^(acrylate)D_(y)M. This redistribution is performed using a xylenesolution of commercial MQ resin, using triflic acid as preferred acidcatalyst. The POS MD_(x) ^(acrylate)D_(y)M used is as described inexample 2 of German patent 3 810 140. This preparation ofacrylate-functionalized MQ resins also includes steps of neutralization,for example with sodium carbonate, and then of removal of the solidresidues by filtration.

American patent U.S. Pat. No. 5,510,430 concerns the functionalizationof resins of MQ type with a whole range of functional groups, forexample aryl, alkyl, vinyl or Si—H. The functionalization process usedis based on the redistribution of disiloxanes. The examples morespecifically disclose the redistribution of MQ resins of formula:[(CH₃)₃SiO_(1/2)]_(0.65)[SiO_(4/2)]₁ dissolved in toluene, by placing incontact with tetramethyldisiloxane and an acid catalyst that may be aphosphonitrile chloride, a linear phosphazene or triflic acid (example6). This is therefore a redistribution MQ+M′₂ at the reflux temperatureof the solvent, with quenching of the reaction by using methanol,resulting in precipitation. Filtration and washing steps are thenperformed.

It emerges from this review of the prior art that the redistribution ofMQ resins using functional oligo-organosiloxanes or functionalpolyorgano-siloxanes, in the presence of triflic acid derivatives, isnot known.

Moreover, it appears that it would be entirely desirable to improve theknown processes, especially in terms of functionalization yields anddegrees of conversion of the POSs used for functionalization (M′2).

Under these circumstances, one of the essential objects of the presentinvention is to provide an improved process for functionalizing siliconeresins comprising siloxyl units M and Q, by redistribution using POSsbearing functional units or units for functionalization; this improvedprocess needing to afford improvements in terms of ease of use,significant increase in the degree of functionalization of theredistributed resin and also of the degree of conversion of thefunctional POS reagents, while at the same time keeping the cost of theprocess as low as possible.

Another essential objective of the invention is to provide a new acidiccatalytic system which is useful or for the functionalization ofsilicone resins comprising units M and Q, by redistribution, using aredistribution reagent consisting of a POS bearing functional units orunits for functionalization, said catalytic system having propertiessuch that it allows an improvement in the redistribution kinetics andalso in the yield and degree of conversion of the reaction, and does sowithout entailing any methodology complications or prohibitive costincreases.

Another essential objective of the invention is to significantly improvethe homogeneous or hetero-geneous catalysis of the reactions forfunctionalization of resins comprising siloxyl units M and Q byredistribution, using POSs bearing functional units or units forfunctionalization. The targeted improvement should be reflected in termsof the control, reliability and production efficiency of thecorresponding industrial processes.

Another objective targeted through the improvement of the catalyticsystem is that of improving the quality of the functionalized MQ resinsobtained, while at the same time optimizing the safety and minimizingthe ecotoxic impact of the industrial processes under consideration.

Another essential objective of the invention is to provide a process forthe functionalization of silicone resins MQ by redistribution, in whichthe yield of incorporation of the POS for functionalization (M′₂) issignificantly increased relative to those obtained by the knownprocesses.

Another essential objective of the invention is to provide a process forthe functionalization of silicone resins MQ by redistribution using POSfor functionalization, which process offers the possibility ofcontrolling the content of functionalities introduced and also thelocation of these functions on the resin.

Another essential objective of the invention is to propose a process forthe functionalization of silicone resins of MQ type by redistribution,this process being able to be applied to a wide variety of chemicalfunctions, so as to be able to produce a large variety of functional MQresins adapted to a host of applications, from a starting materialconsisting of a resin core on the periphery of which are placed selectedchemical functions.

These objectives, among others, are achieved by the present invention,which relates firstly to a process for preparing functionalizedpolyorganosiloxane (POS) resins comprising units M: (R₃SiO_(1/2)), Q:(SiO_(4/2)) and M′: (Y_(a)R_(3−a)SiO_(1/2)) and optionally D:(R₂SiO_(2/2)) and/or D′: (RYSiO_(2/2)) and T: (RSiO_(3/2)) and/or T′:(YSiO_(3/2)),

with, in these units:

-   -   the radicals R, which may be identical or different,        representing a C₁-C₁₀ alkyl or a C₈-C₁₂ aryl,    -   the radicals Y being identical or different and representing a        functional group Y,        by redistribution of POS resins using POSf bearing functional        units M′ and/or D′ and/or T′, as defined above, in the presence        of an acid catalyst,        said process being characterized in that at least one catalyst        is used of formula (I) below:

(C_(m)F_(2m+1)SO₂)_(n)A  (I)

in which:

-   -   Δm is an integer greater than or equal to 1;    -   Δn is an integer equal to 1 or 2 and A represents NH₂ or NH        with:        -   (i) n=1 and A=NH₂ or NHR with R being a radical of SO₂-Z            type with Z being a group other than C_(m)F_(2m+1)        -   (ii) n=2 and A=NH.

It is necessary for the acid catalyst to be liquid under the workingconditions. Furthermore, the choice of the catalyst may be guided by thegas-phase acidity scale described by I. Koppel et al., J. Am. Chem.Soc., 116 (1994) 3047. Thus, the acids used should be those whoseacidity measured in the gas phase is greater than that of sulfuric acid,thus, in terms of ΔG<302 Kcal/mol. For example, (CF₃SO₂)₂NH ΔG=292Kcal/mol, (C₄F₉SO₂)₂NH AG=284 Kcal/mol.

It is thus seen that one of the essential constituent means of theinvention concerns the catalytic system formed by three specificclasses, (I) (i), (I) (ii) and (I) (iii), of triflic acid derivatives.

The use of this catalytic system makes it possible to obtain yields forincorporation of POSs bearing functional units (for example M′₂) ofgreater than 50%, preferably 60% and even more preferably 70%, to becompared with yields obtained in the processes according to the priorart having an upper limit of 30%.

The performance qualities obtained by virtue of this selection oftriflic acid derivatives are entirely surprising and unexpected, notonly in terms of yield of incorporation of POSf, but also as regards thedegree of functionalization, i.e. the content of Si-function units inthe resin MQ. Specifically, this degree is greater than 2.5% by weightand preferably greater than 3% in terms of the redistribution.

Moreover, the specifications of reduced cost, ease of use, safety andlimited or even zero ecotoxicity are largely satisfied by the processaccording to the invention.

The catalytic system according to the invention is also noteworthy interms of kinetics.

Furthermore, the redistribution may be readily stopped by neutralizationof the acid catalyst using a base (for example NaHCO₃, Na₂CO₃, CaCO₃,etc.) and/or by deactivation by heat.

The neutralization is all the more simple since the residual acidity inthis case is markedly lower than that obtained after conventionalredistribution catalysis. In addition, the neutralization has theadvantage that the final reaction medium is not corrosive toward thefunctionalized MQ silicone resins. The stability of these resins withrespect to temperature and storage is thereby greater.

Still regarding this stability aspect of the redistributed resin, it mayalso be pointed out that, since the catalytic system is present in traceamount in the reaction medium, it is nondegrading with respect to theproducts used and/or the products obtained after redistribution.

This process also makes it possible to control the degree offunctionalization of the MQ resin, or even the location of its functionson the resin. Thus, starting with an MQ resin core, for convenience, itis possible to construct around this core a functional peripheralstructure, by customizing the morphology and hydrodynamic volume of theresin. For example, it may be envisaged to produce on the core hair madeof POS segments of (D)_(x) type.

According to one advantageous version a mixture of catalysts is employedcomprising at least one catalyst of formula (I) as defined above and atleast one catalyst of formula (I′) below:

(C_(m)F_(2m+1)SO₂)OH  (I′)

in which m is an integer greater than or equal to 1.

The functions that may be incorporated into the resin are, for example,of Si—H, Si-Vi, Si-phenyl, Si-alkyl, Si-alkenyl, Si-alkyne, Si-alkylhalide, Si-alkyl epoxide, Si-alkyl-polyether, Si-carbinol,Si-alkylammonium, Si-alkylcarboxylic acid or Si-alkylthiol type. It maythus be hoped to be able to provide functional resins adapted to a hostof applications.

In point of fact, it may be envisaged to provide a tree produced from anindustrial MQ-based resin.

Thus, the functions provided by the POSf are such that Y isadvantageously chosen from the group comprising:

-   -   hydrogen    -   an alkenyl    -   an alkynyl    -   an aryl (preferably a phenyl)    -   an (alkyl)epoxy    -   an ether or a polyether    -   a carboxylic acid    -   an amide    -   an amine    -   a halide    -   an alcohol    -   a thiol or any other sulfur derivative.

In accordance with the invention, the starting MQ resins may be eitherunfunctionalized or already functionalized.

As regards the unfunctionalized MQ resins, they are commercial products,for example of formula (M_(x)Q_(y)), with x between 0.5 and 1 and ybetween 0 and 1.

The already-functionalized MQ resins are especially those obtained bythe process in accordance with the present invention fromunfunctionalized starting MQ resins or by the synthetic process startingwith sodium silicate described in U.S. Pat. No. 2,676,182.

Advantageously, the starting MQ resin is in the form of a solution in anorganic solvent, for instance xylene or toluene.

As regards the POSfs bearing functional units M′ and/or D′ and/or T′,which are useful for the redistribution, it will be preferred to usethose of formula (IV.1), (IV.2) or (IV.3) below:

in which:

-   -   Y and R are as defined above,    -   a and b=0 to 2,    -   0≦x≦200 and preferably 0≦x≦50,    -   0≦y≦200 and preferably 0≦y≦50,    -   with the condition that if x+y=0, then a and/or b≠0,    -   1≦x′≦10 and preferably 1≦x′≦8,    -   0≦y′≦10 and preferably 0≦y′≦3,    -   3≦x′+y′≦10 and preferably x′+y′=3, 4 or 5.

The POSfs of formulae (IV.1), (IV.2) and (IV.3) correspond,respectively, to disiloxanes, linear polyorganosiloxanes and cyclicoligoorganosiloxanes.

These POSfs are, for example, M₂, M₂ ^(Vi), MD_(x)M, MD_(x)D′_(y)M,M′D_(x)D′_(y)M′, MD_(x)D_(y) ^(Vi)M′, MD_(x)D_(y) ^(Vi)M,M^(Vi)D_(x)D_(y) ^(Vi)M^(Vi), M′D_(x)M′, M^(Vi)D_(x)M^(Vi), D_(x′)^(Vi)D_(y′).

It should be noted, as regards the acid catalyst of formula (I) (i) or(ii) or (iii) that the fluoro chain C_(m)F_(2m+1) may be extended so asto increase the acidity of the catalyst and subsequently its efficacy.

In practice, the acid catalysts may be, for example:

I(i) n=1 and A=OH

I(ii) n=1 and A=NH₂ or NHR with R being a radical of SO₂-Z type with Zbeing a group other than C_(m)F_(2m+1)

I(iii) n=2 and A=NH.

The chosen catalyst preferably has a melting point lower than thereaction temperature, so that the catalyst is in the liquid state duringthe reaction.

In the preferred embodiment of the process according to the invention,the catalyst is trifluoro-methanesulfonimide acid of formula (I) (ii)with m=1 and A=NH₂.

In quantitative terms, it may be pointed out that the concentration ofacid catalyst (I) is advantageously between 1 ppm and 2% relative to thestarting resin. Moreover, the catalyst (I)/inert support (preferablycarbon black) mass ratio is preferably between 0.1 and 10, and ispreferably of the order of 1.

In accordance with the invention the catalysis may be homogeneous orheterogeneous. It is preferably homogeneous, the catalyst being in thiscase dissolved in the reaction medium.

According to a variant of heterogeneous catalysis, the catalyst is atleast partially absorbed onto an inert support which may be, forexample, carbon black or silica.

The process according to the invention may be defined by othermethodological characteristics, and in particular in that it comprisesthe following essential steps:

-   -   1—combining the starting POS resin, the POSf bearing functional        units, the acid catalyst (I)— optionally supported—in an organic        solvent;    -   2—reacting preferably at a temperature θr greater than or equal        to room temperature and less than or equal to the boiling point        of the solvent, and even more preferably between 50° C. and 100°        C.;    -   3—optionally quenching the reaction by adding an agent for        neutralizing the acid catalyst (I);    -   4—optionally removing the supported acid catalyst (I) from the        reaction medium, preferably by filtration.

Advantageously, as has already been mentioned above, the organicsolvent, preferably xylene and toluene, is provided in the reactionmedium by means of a solution of starting POS resin (MQ) in saidsolvent. It is also possible to work with an excess of functionalizedsilicone oil.

The process of functionalization by redistribution according to theinvention makes it possible especially to graft Si—H and/or Si-alkenyl(preferably vinyl) units onto MQ resins. Given that these functions H oralkenyl are reactive functions, among others, it may be envisaged, inaccordance with the invention, to perform a second functionalizationaccording to a hydrosilylation mechanism, so as to covalently attach asecond functional segment onto the already functionalized MQ resin.

This corresponds to the case in which Y represents H or alkenyl in thefunctional units M′ and/or D′ and/or T′, of the POSf. In this variant,after the redistribution, other functionalization radicals Y₁ bearing atleast one unsaturation (preferably ethylenic) or at least one Si—H unitare grafted onto the ≡Si—H or ≡Si-alkenyl units, respectively, of theredistributed resin.

As regards the methodology, it may also be pointed out that it ispreferable, in order for the redistribution to proceed correctly, forthe reaction atmosphere to be free of moisture. Thus, the process isadvantageously performed under an atmosphere of neutral gas, for exampleargon or nitrogen.

The reaction pressure is advantageously normal and the reactiontemperature may range from room temperature (for example 25° C.) to atemperature of 150° C. or more.

The redistribution is stopped by means of deactivating the catalyst.Since it is an acid catalyst, in this instance triflic acid orderivatives thereof, the deactivation may be performed using a basicneutralizer, for instance sodium carbonate Na₂CO₃ or sodium bicarbonateNaHCO₃.

The neutralization is all the more necessary when the catalysis ishomogeneous catalysis, since, in such a case, in contrast toheterogeneous catalysis, the catalyst is not removed at the end of thereaction.

According to one variant of the process in accordance with theinvention, the redistributed and functionalized resin obtained issubjected to at least one other redistribution/functionalization, usingPOS bearing functional units.

The invention also relates to a catalytic system that is useful forpreparing functionalized polyorganosiloxane (POS) resins comprisingunits M: (R₃SiO_(1/2)), Q: (SiO_(4/2)) and M′: (Y_(a)R_(3−a)SiO_(1/2))and optionally D: (R₂SiO_(2/2)) and/or D′: (RYSiO_(2/2)) and/or T:(RSiO_(3/2)) and/or T′: (YSiO_(3/2)) with, in these units:

-   -   the radicals R being identical or different and representing a        C₁-C₁₀ alkyl or a C₈-C₁₂ aryl;    -   the radicals Y being identical or different and representing a        functional group Y, preferably chosen from the group comprising:        -   hydrogen        -   an alkenyl        -   an alkynyl        -   an aryl (preferably a phenyl)        -   an (alkyl)epoxy        -   an ether or a polyether        -   a carboxylic acid        -   an amide        -   an amine        -   a halide        -   an alcohol        -   a thiol or any other sulfur derivative by redistribution of            POS resins using POSs bearing functional units M′ and/or D′            and/or T′ as defined above,            characterized in that it comprises at least one catalyst of            formula (I) below:

(C_(m)F_(2m+1)SO₂)_(n)A  (I)

in which:

-   -   Δm is an integer greater than or equal to 1;    -   Δn is an integer equal to 1 or 2 and A represents OH, NH₂ or NH        with:        -   (i) n=1 and A=NH₂ or NHR with R being a radical of SO₂-Z            type with Z being a group other than C_(m)F_(2m+1)        -   (ii) n=2 and A=NH        -   (iii) n=1 and A=OH.

This catalytic system is markedly more efficient than the conventionalcatalysts for the redistribution of silicone resins MQ using only TFOH.In terms of kinetics, conversion and yield, it makes it possible toobtain high-quality functionalized MQ resins, the functionality of whichis controlled and adapted to the intended use. These performancequalities are all the more advantageous since they are obtained withoutsacrificing the imperatives of cost, safety, absence of ecotoxicity andease of use.

The examples that follow will make it possible to understand moreclearly the process and the catalyst according to the invention, byhighlighting all their advantages and the possible implementationvariants.

EXAMPLES I-Comparative Example Tonsil Catalyst

500 g of a xylene solution containing 300 g of resin (M_(x)Q_(y))_(z)(structure determined by ²⁹Si NMR:(M_(0.88)M′_(0.06)D*_(0.05)Q₁*)_(Z−)M/Q=0.9) are introduced into a 1liter reactor under nitrogen. 30 g of M′₂ (1.49 mol SiH/kg) and 2.7 g ofTonsil are added. The mixture is brought to 70° C. and heated at thistemperature for 7 hours. After cooling to room temperature, the reactionmass is filtered through cardboard and then through a 0.45 μm PTFEfilter to remove the Tonsil. During the test, several samples are takenand make it possible to monitor the amount of SiH bound to the resin andalso the nature and relative proportions of the light fractions in thereaction medium as a function of the reaction time.

TABLE 1 Reaction time 0 h 1 h 3 h 6 h 7 h Amount of SiH on the resin 0%0.8% 1.2% 1.47% 1.39% (quantification by IR) Conversion of M′₂ 0%  52% 74%   78%   82% (quantification by GC)Final structure of the resin (29Si NMR):(M_(0.82)M′_(0.08)D*_(0.05)Q₁*)_(z)Final yield of incorporation of SiH: 32%.

II-Comparative Test Tonsil Catalyst

500 g of a xylene solution containing 300 g of resin (M_(x)Q_(y))_(z)(NMR analyses: (M_(0.9)D*_(0.02)Q₁)_(z) with M/Q=0.9 (molar)) areintroduced into a 3 liter reactor under nitrogen. This solution isbrought to 70° C. and 30 g (1.49 mol SiH/kg) of M′₂ and 2 g of Tonsilare added. The mixture is left to react for 7 hours at 70° C. Thereaction mass is cooled and filtered through cardboard+0.45 μm PTFEfilter to remove the Tonsil. During this test, a certain number ofsamples are taken, which make it possible to monitor the amount of SiHunits as a function of time:

T=0: 0%, T=1 h: 0.8%, T=3 h: 1.2%, T=7 h: 1.47%, or 1.39% (IR), i.e.0.48 mol SiH/kg of resin.

The yield for incorporation of the SiH units is 32%. The NMR analysesshow that the structure of the final resin is:(M_(0.8)M′_(0.07)D*_(0.04)Q₁)_(z).

III-Comparative Example CF₃SO₃H Catalyst

The operating conditions are the same as those described in example I.

Materials added: 500.0 g of xylene solution, i.e.

-   -   300 g of resin    -   30.0 g of M′2, i.e. 1.47 mol/kg    -   1.31 g of CF₃SO₃H        Reaction time: 7 hours        Monitoring of the reaction:

TABLE 2 Reaction time 0 h 1 h 3 h 6 h 7 h Amount of SiH on the 0% 2.79%3.17% 3.08% 3.28% resin (quantification 3.37% by KOH assay) (I)Conversion of M′₂ (%) 0% 94.5%   97%   97%   97% (quantification by GC)Final structure of the resin (²⁹Si NMR):(M_(0.72)M′_(0.11)D*_(0.04)Q₁*)_(z)Final yield of incorporation of SiH: 75%.

IV-Example CF₃SO₂)₂NH Catalyst

The operating conditions are the same as those described in example I.

Materials added: 500.3 g of xylene solution, i.e.

-   -   310 g of resin    -   31.6 g of M′₂, i.e. 1.49 mol/kg 2.46 g of TFSI        Reaction time: 6 hours        Monitoring of the reaction:

TABLE 3 Reaction time 0 h 1 h 3 h 6 h Amount of SiH on the 0% 2.87%3.23% 3.04% resin (quantification 3.30% by KOH assay) (IR) Conversion ofM′₂ (%) 0%   95%   97%   97% (quantification by GC)Final structure of the resin (²⁹Si NMR):(M_(0.74)M′_(0.11)D*_(0.04)Q₁*)_(z)Final yield of incorporation of SiH: 76%.

V-TFSI catalysis test

Same operating conditions as for example I:

-   -   500 g of xylene solution containing 300 g of resin M_(x)Q_(y)    -   30 g of M′₂, i.e. 1.49 mol of SiH/kg of resin    -   2.46 g of TFSI

-   reaction time: 7 hours    IR assay: 1.05%, mol SiH/kg of resin

SiH assay after 1 hour reaction: 1.07 mol SiH/kg,

3 hours: 1.03 mol SiH/kg of resin

-   yield of SiH incorporation: 70%-   final resin structure: (M_(0.7)M′0.12D*_(0.05)Q₁)_(z)

VI-CF₃SO₃H Catalysis Test

Same operating conditions as for example I:

-   -   642.1 g of xylene solution containing 400 g of resin        (M_(x)Q_(y))_(z)    -   47.21 g of M₂ ^(Vi), i.e. 1.27 mol of Si-vinyl/kg of resin    -   2.45 g of carbon black    -   1.71 g of CF₃SO₃H

-   reaction time: 8 hours 10 minutes    IR assay: 1.1 mol Si-vinyl/kg of resin

-   yield of SiH incorporation: 87%≧

-   final resin structure: (M_(0.76)M_(0.11) ^(Vi)D*_(0.03)Q₁)_(z).

1. A process for preparing functionalized polyorganosiloxane (POS) resins comprising units M: (R₃SiO_(1/2)), Q: (SiO_(4/2)) and M′: (Y_(a)R_(3−a)SiO_(1/2)) and optionally D: (R₂SiO_(2/2)) and/or D′: (RYSiO_(2/2)) and T: (RSiO_(3/2)) and/or T′: (YSiO_(3/2)) wherein: the radicals R, which are identical or different, represent C₁-C₁₀ alkyl or C₈-C₁₂ aryl; and the radicals Y, which are identical or different, represent a functional group Y selected from the group consisting of hydrogen, alkenyl, alkynyl, aryl, (alkyl)epoxy, ether, polyether, carboxylic acid, amide, amine, halide, alcohol, thiol and other sulfur derivative; said process comprising conducting are distribution reaction between a POS resin and a POSf compound bearing functional units M′ and/or D′ and/or T′, as defined above, in the presence of an acid catalyst, wherein at least one catalyst has formula (I) below: (C_(m)F_(2m+1)SO₂)_(n)A  (I) wherein: m is an integer greater than or equal to 1; and n is an integer equal to 1 or 2 and A represents NH₂ or NH with: (i) n=1 and A=NH₂ or NHR with R being a radical of SO₂-Z type with Z being a group other than C_(m)F_(2m+1); or (ii) n=2 and A=NH.
 2. The process as claimed in claim 1, wherein a mixture of catalysts is employed comprising at least one catalyst of formula (I) and at least one catalyst of formula (I′) below: (C_(m)F_(2m+1)SO₂)OH  (I′) wherein m is an integer greater than or equal to
 1. 3. The process as claimed in claim 1, wherein Y is phenyl.
 4. The process as claimed in claim 2, wherein Y is phenyl.
 5. The process as claimed in claim 1, wherein the catalyst of formula (I) is trifluoromethanesulfonimide acid (TFSI) of formula (I) (ii) with m=1.
 6. The process as claimed in claim 2, wherein the catalyst of formula (I) is trifluoromethanesulfonimide acid (TFSI) of formula (I) (ii) with m=1.
 7. The process as claimed in claim 1, wherein the concentration of acid catalyst (I) is between 1 ppm and 2% by weight relative to the starting resin.
 8. The process as claimed in claim 1, comprising the following essential steps: (1) combining the starting POS resin, the POSf bearing functional units and the acid catalyst (1) in an organic solvent; (2) reacting at a temperature Or greater than or equal to room temperature and less than or equal to the boiling point of the solvent; and (3) optionally quenching the reaction by adding an agent for neutralizing the acid catalyst (I).
 9. The process as claimed in claim 8, wherein the reaction temperature is between 50° C. and 100° C.
 10. The process as claimed in claim 8, wherein a mixture of catalysts is employed comprising at least one catalyst of formula (I) and at least one catalyst of formula (I′) below: (C_(m)F_(2m+1)SO₂)OH  (I′) wherein m is an integer greater than or equal to
 1. 11. The process as claimed in claim 8, wherein the catalyst of formula (I) is trifluoromethanesulfonimide acid (TFSI) of formula (I) (ii) with m=1.
 12. The process as claimed in claim 8, wherein the organic solvent is provided in the reaction medium by means of a solution of starting POS resin in said solvent.
 13. The process as claimed in claim 12, wherein the organic solvent is xylene or toluene.
 14. The process as claimed in claim 1, wherein Y=H or alkenyl in the functional units M′ and/or D′ and/or T′ of the POSf, and wherein, after the redistribution, other functionalization radicals Y₁ bearing at least one unsaturation or at least one Si—H unit are grafted by hydrosilylation onto the ≡Si—H or ≡Si-alkenyl units, respectively, of the redistributed resin.
 15. The process as claimed in claim 14, wherein other functionalization radicals Y₁ bearing at least one ethylenic unsaturation are grafted by hydrosilylation onto the ≡S—H or ≡S-alkenyl units, respectively, of the redistributed resin. 